Test could help screen patients for side effects from cholesterol drugs

WASHINGTON - Scientists may have found a way to test for and possibly avoid the most serious side effect of cholesterol-lowering statin drugs, one of the top-selling medicines in the world.

In rare cases, statins can cause muscle pain and weakness.

Researchers have identified a genetic variation that seems to predict more than half of these cases. People on statins who have the variant were about five to 17 times more likely to develop muscle problems, a serious side effect that can lead to muscle breakdown, kidney failure, and death.

The finding raises hope that a test could be developed to screen heart patients to find out who is at greatest risk. Normally, muscle weakness caused by statins affects 1 out of 10,000 patients a year.

"It could become a very simple check," said Rory Collins of the University of Oxford, who co-wrote the study published in the latest New England Journal of Medicine.

But doctors say having this knowledge doesn't mean the millions taking statins should be tested, especially those who are having no problem. "I would recommend extreme caution in testing for this," said Dr. James Stein, a University of Wisconsin-Madison cardiologist who had no role in the research. "It could potentially lead to people not taking life-saving drugs just because there's an excess risk" of a side effect.

The genetic analyses drew from two previous large studies that were in part funded by Merck & Co., which makes the onetime cholesterol blockbuster, Zocor, now available as the low-cost generic simvastatin.

The first involved 85 statin users with muscle weakness and 90 control patients taken from a sample of 12,000 people. The participants took higher-than-normal doses of simvastatin.

Using DNA, researchers found a gene variation in more than 60 percent of those with muscle weakness. The variant makes a protein less effective at carrying statins into the liver where the drug has the greatest effect.